Pyrotechnical fuse with a detonator displaceable from a safe position into a live position

ABSTRACT

A fuse structure for an explosive device such as a hand grenade. The fuse structure has a detonator normally disposed in a noneffective safety position. A charge in the fuse structure is ignited when the grenade is released from the hand and is operable to release the detonator to effective position. The detonator carries a charge which is ignited only after the detonator has been released from ineffective position. The detonator charge will be operable for igniting a further charge which will detonate the explosive device only when the detonator is in effective position.

[ 51 Aug. 15, 1972 United States Patent Bedall et al.

[56] References Cited UNITED STATES PATENTS [54] PYROTECHNICAL FUSE WITHA 3,505,959 4/1970 Lohnert et a1. ..........l02/65 X Numberg; Max Re mFurth; Dieter Buddey, Pnmary Exarmner-Verhn R. Pendegrass Number-g, allof Germa Attorney-Wa.lter Becker ABSTRACT A fuse structure for anexplosive device such as a hand grenade. The fuse structure has adetonator normally disposed in a noneffective safety position. A chargein the fuse structure is ignited when the grenade is released from thehand and is operable to release the detonator to effective position. Thedetonator carries a charge which is ignited only after the detonator hasbeen released from ineffective position. The detonator charge will beoperable for igniting a further charge which will detonate the explosivedevice only when the detonator is in effective position.

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sum 2 OF 2 INVENTOR. Hang B554 By Ha Eff/725511 Die/H UUCVLE/PYROTECI'INICAL FUSE WITH A DETONATOR DISPLACEABLE FROM A SAFE POSITIONINTO A LIVE POSITION The present invention relates to a pyrotechnicalfuse with a detonator displaceable from a safe position into a liveposition by driving force while being arrested in said safe position bya safety member.

In connection with fuses for projectiles it is known to arrest adetonator in its safe position by a pyrotechnically releasable safetymember. After the projectile has been fired, the detonator is activatedby burning off a' pyrotechnical composition or set adapted to soften thesafety member, whereupon the detonator is by a spring force moved intolive position.

It is an object of the present invention to provide safety means forfuses equipped with pyrotechnical sets for hand grenades which willassure a maximum safety of operation.

It is another object of the present invention to provide a hand grenadeequipped with a fuse, which during customary use will detonate onlyafter the grenade has reliably left the position from which it has beenthrown and after a certain time has passed.

It is still another object of this invention to provide a hand grenadeas set forth in the preceding paragraphs, which is so designed that apremature detonation cannot be brought about due to a faultymanufacturing step.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings, in which:

FIG. 1 illustrates a longitudinal section through a time delay fuseaccording to the invention.

FIG. 2 shows on a larger scale than FIG. 1 a throttle valve and itsadjacent part as used in the arrangement of FIG. 1.

FIG. 3 represents a modification of a fuse according to FIG. 1.

FIG. 4 is an isometric view of an embodiment which differs somewhat fromthat of FIG. 2.

FIG. 5 is a percussion fuse according to the invention and, morespecifically, a longitudinal section therethrough.

FIG. 6 shows a modification of a portion of the fuse of FIG. 5.

The pyrotechnical fuse according to the present invention ischaracterized primarily in that a carrier for a detonator, which isconnected to the stationary part of the fuse through the intervention ofa pyrotechnically releasable safety member, is mounted in a tubular fusehousing having its lowermost part provided with a secondary charge andis axially displacable therein and is adapted by a driving force to bemoved with its detonator cap into the secondary charge where it isignitable by a pyrotechnical composition or set as soon as thepyrotechnical set ignited by an igniter cap has released the safetymember, said safety member being adapted to prevent an ignition of thedetonator charge and of the secondary charge as long as the detonatorcarrier has not moved to its live position.

As safety member there may be employed a flap valve the flap of which insafety position is supported by an insulating disc and in live positionis adapted to be bent open by the fire jet of the pyrotechnical set.

Within the range of the secondary charge, a cupshaped insert may beprovided for receiving the detonator cap while the bottom of the insertmay have a conical recess at the side of the secondary charge whichrecess conveys the ignition shock from the detonator charge to thesecondary charge only when the detonator cap is inserted into theinsert. As a further safety measure, the detonator charge may beinserted into a tubular detonator cap which is produced ornon-splintering material and the outlet cross-section of which at leastequals the maximum inner transverse pipe section while the outerdiameter corresponds to the inner diameter of the insert. Furthermore,between the ignition cap and the detonator there may be provided athrottle valve. Advantageously, the driving force may be produced by ahelical pressure spring, and the pyrotechnically releasable safetymember may be designed as a fusable member.

When a percussion fuse in involved, the stationary part of the fusehousing may have in a pendulum-like manner mounted therein a strikerwhich is provided with an ignition passage. The said striker is in thesafety position of the detonator fixed in radial and axial direction bythe detonator carrier arrested by the safety member while the headportion of the striker is surrounded by a fuse composition which afterdisplacement of the detonator carrier to itslive position is adapted toignite on theimpact of the grenade by deviating the striker. By means ofa rubber-elastic buffer located between the striker and the detonatorcarrier, a safe mounting of the fuse will be assured.

If the pyrotechnical set should prematurely be ignited, the ignition jetwill rebound from the closed flap valve and, therefore, cannot ignitethe detonator charge being in its safety position. The heat produced bythe pyrotechnical set is kept away from the detonator charge by aninsulating disc. Therefore, also an ignition of the detonator charge byoverheating will be impossible. If the detonator charge willnevertheless be ignited while being in its safety position, the bottomof the cup-shaped insert will prevent the transfer of an ignition shockto the secondary charge inasmuch as the ignition shock effective at theinsert bottom will be able to bend the bottom into the conical recesswithout affecting the secondary charge. The throttle valve will duringthe absence of a pyrotechnical set and during the absence of a flapvalve prevent the ignition jet of the ignition cap from igniting thedetonator charge.

With a percussion fuse equipped with a striker, a further safety step isrealized by the fact that when a hand grenade has not been thrown farenough from its starting point so that its impact occurs before thestriker has been released by the detonator, the grenade will after theexpiration of a certain time be live but due to the failure of a furtherimpulse of movement will not be detonated and thus will not endanger thesoldier. On the other hand, the ignition of the activated detonator willbe effected already at a small impulse of movement as it may be broughtabout when the grenade rolls off in response to a corresponding movementof the striker.

A detonator safety device consists in that the detonator after releasingthe fuse cap will remain in safety position until after about two-thirdsof the delaying time the meltable member is softened by thepyrotechnical set. Thus, the detonator is only then moved by the helicalspring into its live position. The ignition of the fuse cap can beeffected only when the grenade has left the hand of the person throwingthe grenade. By these safety devices it will be assured that the handgrenade can be thrown at any rate without endangering the respectivesoldier while on the other hand the enemy soldier will with a properfunctioning of the fuse not have sufficient time to throw back the handgrenade.

Referring now to the drawings in detail, a tubular fuse housing 1 of atime delay fuse shown in its basic position in the drawing is screwedonto a head portion 2. Linked to the head portion 2 through theintervention of a bolt 3 is a yoke or the like 4 which is secured in itssafety position by a safety pin or cotter pin or the like designated byreference numeral 5. Yoke 4 is on its inside engaged by a preloadedspring plate 6. An arm 7 with hammer 9 is through the intervention of aspring 8 pivotally arranged on the bolt 3. An ignition cap 10 isconnected in an ignition cap carrier 11 which is positively connected tothe upper end of a member 14 in the fuse housing 1. Between the ignitioncap carrier 11 and a pyrotechnical delaying set 13 there is provided achamber 12. The delaying set 13 is at the lower end of the member 14(see FIG. 2) closed by a throttle valve 15 which has the shape of a cupand is provided with radially extending bores 16 and a flap valve 17.The flap valve 17 is connected by a unilateral flanging of thesleeve-shaped member 14.

A tubular detonator carrier 19 is approximately halfway placed over themember 14 and has its upper end connected to the member 14 by means ofan annular melting member or fuse 18. Between a collar 14 of the member14 and the end face 20 of the detonator carrier 19 there is provided aloaded helical pressure spring 21. At the lower end of the detonatorcarrier 19 there is screwed-in a detonator cap 22 with a detonatorcharge 23. A heat insulating disc 24 adapted to release the ignitionpassage 23' to the detonator charge 23 and preferably made oftetrafluorethylene is firmly mounted on the detonator cap 22 and engagesthe flap valve 17.

A carrier body 26 for a secondary charge 27 with positively connectedcup-shaped insert and a secondary charge 27 is screwed to the lower endof the fuse housing 1. Between the carrier body 26 and the detonator cap22 there is provided an intermediate chamber 23". The insert bottom 28has a coaxially arranged conical recess 29. The secondary charge 27 isseparated from the recess 29 and from the non-illustrated explosivecharge of a hand grenade indicated in dot-dash lines by coaxial plates30 and 31. Instead of the throttle valve 15 between the pyrotechnicalset 13 and the detonator 22, it is possible for the same purpose andwith an analogous effect to employ a disc 32 (FIG. 3) between theignition cap 10 and the set 13. This disc 32 comprises an annulararrangement of a plurality of eccentrically arranged bores 33 and in thepart 14 is connected to the wall of the chamber 12 upsetting.

A flap valve 34 illustrated in FIG. 4 comprises a circular disc which isfolded at the part 14 and which comprises a hinge-like web 36 betweenthe ends of an annular groove 35.

The percussion fuse illustrated in its basic position in FIG. 5 differsfrom the time delay fuse shown in FIGS. 1-4 merely as to the followingdetails.

In a part 37 there are provided two chambers 12 and 38 which areseparated from each other. A pyrotechnical set 39 for the fusable member18 is arranged in the upper chamber 12 whereas a head portion 41 withignition set pertaining to a striker equipped with an ignition passage42 extends into the lower chamber 38. The striker 43 is mounted in apendulum-like manner in a disc 44 which is connected to the lower end ofpart 37. The foot portion 45 of the striker 43 is positively arranged ina recess 46 of the detonator carrier 19 while at the bottom of therecess there is provided a rubberelastic buffer 47. The lower opening ofthe ignition passage is closed by the flap valve 17. A cup-shapedignition set 48 shown in FIG. 6 is connected to a sleeve 49 in the lowerchamber 38. The head portion 50 extends in a contact-free manner intothe ignition set 48. The effect of this arrangement is analogous to thatdescribed in connection with FIG. 5.

Function of the time relay fuse of FIG. 1.

When the safety pin 5 has been removed, the yoke 4 is by means of thespring plate 6 and by the preloaded spring 8 pivoted incounter-clockwise direction while eventually yoke 4 and plate 6 arethrown off from the head portion 2. Subsequently, the hammer 9 hits thefuse cap 10 as a result of which the pyrotechnical delaying set 13 isignited. The heat produced by the delaying set 13 softens up the fuse 18so that the helical spring 21 will be able to press the detonatorcarrier 19 downwardly into its live position. In this position, thedetonator cap 22 with its lower opening will be located at the insertbottom 28. Only at the end of the burning of the delaying set 13, theflap valve 17 is by a fire jet bent open which will then through theignition passage 23' hit the detonator charge 23. This initiating shockof the detonator charge 23 impacts directly upon the insert bottom 28and ignites the secondary charge 27 which initiates the detonation ofthe hand grenade. If the working of the fuse is irregular, the followingactions of the safety devices will take place.

When the detonator carrier 19 is in its safe position, it will beappreciated that at a premature ignition of the delaying set 13, theflap valve 17 will prevent the fire jet from igniting the detonatorcharge 23. The valve 17 cannot be bent open because of the adjacent heatinsulating disc 24. An ignition of the detonator charge 23 can,therefore, not be realized by bending open the flap valve 17 nor by aheat flow.

If the delaying set 13 and the flap valve 17 are missing, an ignition ofthe detonator charge 23 in its safe position is prevented by thethrottle valve 15. The fire jet of the fuse cap 10 will impact upon thethrottle valve 15 while only a minor portion of the ignition jet energypasses through the lateral bores 16 into the adjacent hollow chamberwhere it is subjected to turbulence. This minor portion of the ignitionjet is insufficient for igniting the detonator charge 23.

If it has been overlooked to insert the delaying set 13, the flap valve17 and the throttle valve 15, and if therefore the detonator charge 23is ignited in its safety position, the initiating shock of the detonatorcharge 23 will spread to all sides in the intermediate chamber 23". Inthis way, the said shock softens to such an extent that the initiatingpressure which is still effective at the insert bottom 28 will beabsorbed by said insert bottom. The insert bottom 28 easily bends intothe recess 29 without affecting the secondary charge 27 If finally thedelaying set 13 is missing, and the detonator carrier 19 would at a timewhen the fuse cap is released occupy its live position, the fire jet ofthe ignition cap will by the throttle valve be weakened to such anextent that the fire jet cannot bend open the flap valve 17 and causeignition of the detonator charge 23. Even if the flap valve 17 would belacking, the energy of the throttled ignition jet would not besufficient to ignite the detonator charge 23. If the fuse has beencorrectly manufactured and if the ignition process takes its normalcourse, the described effect of the respectively built-in throttlevalves 15 and 32 will not take place. Function of the percussion fuse ofFIG. 5.

After the pyrotechnical heating set 39 has been ignited which in view ofthe developed heat softens the fuse member 18, the helical spring 21will press the detonator carrier 19 into its live position. Thedetonator carrier 19 will release the striker 43 which was previouslyarrested in the recess 46 of the detonator carrier 19 in radial andaxial direction, and the flap valve 17 is released. If now the fusereceives a shock, the head part 41 with ignition set 40 impacts upon thewall of the chamber 38. The ignition jet of the ignition set 40 extendsthrough the ignition passage 42 of the striker 43 and bends the flapvalve 17 open so that the ignition jet can unimpededly hit the detonatorcharge 23 which is in live position and can ignite the same. The igniteddetonator charge 23 will then ignite the secondary set 27 and this willinitiate the detonation of the hand grenade.

If the detonator charge 23 accidentally ignites in safety position ofthe detonator carrier 19 while the flap valve 17 is missing, it will beappreciated that, similar to the above described manner, the thusoccurring intitiating shock is absorbed in a cup-shaped insert 25 sothat the secondary charge 27 will not be ignited.

The fuse according to FIG. 5 at the head portion 2 thereof is providedwith a threaded part 51 for screwing or threading into a body 52indicated and outlined for a hand grenade. On axial bolt 3 secured tothe head portion 2 there is journalled a yoke 4 which is secured in therest position thereof by way of a pin 5 engaging in a pertaining bore. Apreloaded spring plate 6 engages against the inner side of the yoke 4thereby endeavoring to pivot the yoke around the axis defined by bolt 3and to let go or release the same.

Further there is a spring 8 wound around the axis of the bolt 3 and thespring 8 has a shank or leg thereof engaging against the head portion 2while a second shank or leg portion thereof abuts against a pivot arm 7which likewise is journalled upon the axis of the bolt 3 and carries ahammer 9 which in turn engages against the spring plate 8 and yoke 4therewith.

In the tubular-formed head portion 2 of the fuse there is inserted adetonator or ignition cap carrier 11 in which an ignition cap 10 isintroduced centrically therewith. A cylindrical part 37 is connectedwith the ignition cap carrier 11 and a heating set 39 is pressed into acylindrical recess thereof. A tubular-formed detonator carrier 19 isconnected with the part 37 by way of an annular or ring-formed meltingmember 18 and a screw pressure spring 21 is held between the upper edgeof the carrier 19 and a flange of the part 37.

In the part 37 there is further provided a chamber 38 which is closed bya disc 44 fastened in the part 37 by way of flange means or edgefastening. This disc 44 serves for pivotable journalling of a striker 43which projects into the chamber 38 with a head part 41 provided with anignition set 40. Additionally, the striker is held with a base or footportion 45 in complementary fit in a recess 46 of the detonator carrier19. Finally, the striker 43 is provided with an ignition passage 42which is closed in the base or foot portion 45 by way of a flap valve17. The flap valve 17 is flanged on one side in the base or foot portion45. Between the base or bottom of the recess 46 and the face side of thefoot part 45 there is provided a buffer 47 for damping shock or impact.A detonator cap 22 with detonator charge 23 screwed or threaded into thedetonator carrier 19 pro jects into an intermediate housing chamber 23"of the fuse housing 1. At the end of this fuse housing 1, there isthreaded or screwed an insert 25 with a secondary valve 27.

The fuse according to FIG. 6 provides the same construction as the fuseaccording to FIG. 5 except for the illustrated detail. This detailconsists therein that in the recess 38 of the part 37 there is secured asleeve 49 with a pot-formed igniter set 48 into which a head portion 50of the striker 43 projects without engagement during arresting of thestriker 43. The embodiment and arrangement of disc 44,- ignition passage42 and flap valve 17 have already been described for the correspondingparts in FIG. 5. Function of the percussion fuse of FIG. 6

lf the released striker 43 encounters a shock or impact, then the headportion 50 thereof strikes against the ignition set 48. The ignitionstream of the ignition set 48 passes through the ignition passage 42 andbends open the flap valve 17 in order to ignite the detonator capillustrated in FIG. 5. The further occurring functions of the fuse thencorrespond to the functions described for FIG. 5.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawings but alsocomprises any modifications within the scope of the appended claims.

What is claimed is:

1. In a fuse structure for an explosive device: a tubular housing havinga first ignitable charge at one end operable when ignited to detonatethe explosive device, a detonator member in said housing having a firstposition remote from said first charge and a second position adjacentsaid first charge, said member carrying a second ignitable chargeoperable when ignited to ignite said first charge only when saiddetonator member is in the said second position thereof, biasing meansurging said detonator member toward the said second position thereof, aretainer in said housing engaging said detonator member and holding itin said first position thereof and releasing said detonator member inresponse to ignition of said second charge, a third charge in saidhousing near the end of said housing opposite said first charge, anigniter cap on said housing operatively disposed adjacent said thirdcharge for igniting said third charge when actuated, said third chargebeing operable when ignited to influence said retainer and release saiddetonator member to move to said second position thereof, valve means onthe side of said second charge facing away from said third charge, saidvalve means being held closed by said detonator member when the latteris in the said first position thereof and being released when saiddetonator member moves away from the said first position toward the saidsecond position thereof, and means on the opposite side of aid valvemeans from said second charge operable for igniting said second chargeonly when said valve means is released.

2. A fuse structure according to claim 1 in which said third charge is adelayed action rod-like charge and has one end near said igniter cap tobe ignited thereby and the other end near the side of said valve meansopposite said second charge and provides the said means to ignite saidsecond charge when said valve means is released.

3. A fuse structure according to claim 1 in which said valve meanscomprises a flap valve which is clamped in closed position by saiddetonator member in the said fist position thereof.

4. A fuse structure according to claim 1 in which said valve meanscomprises a disc having a bendable flap element therein, and a clampring for holding said flap element in closed position and disposedbetween said flap element and said detonator member so as to releasesaid flap element only when said detonator member moves away from itssaid fist position.

5. A fuse structure according to claim 1 which includes a cup-likeelement on the side of said first charge facing said detonator memberand opening toward said detonator member so as to receive the end ofsaid detonator member when the latter moves into its said secondposition, the side of said element facing said first charge having acentral conical recess and said element being operable to transmitigniting shock to said first charge only when the end of the detonatormember is disposed in said element.

6. A fuse structure according to claim 5 in which said detonator memberis tubular and is formed of material which will not break when the saidsecond charge is ignited, said detonator member having an outsidediameter slidably fitting in said housing while the end part of saiddetonator member facing said first charge has a diameter receivable inthe open side of said cup-shaped element.

7. A fuse structure according to claim I which includes a choke betweensaid igniter cap and said third charge.

8. A fuse structure according to claim 2 which includes a choke betweensaid third charge and said second charge.

9. A fuse structure according to claim 1 in which said means forigniting said second charge comprises a fourth charge on the side ofsaid valve means opposite said second charge and adapted to becomeignited upon impact, support means in said housing supporting saidfourth charge and engaged by said detonator member in said firstposition thereof so as to be held against movement in said housing whilebeing released for movement in said housing when said detonator membermoves from said first position thereof to said second position thereof,said support means being mov bly connected to said housing for movementof said ourth charge lnto impacting engagement with said housing uponimpacting of said explosive device against a surface.

10. A fuse structure according to claim 9 in which said support meanshas one end facing said detonator member and the said fourth chargemounted on the other end thereof and a passage extending through saidsupport means from end to end thereof.

11. A fuse structure according to claim 1 in which said biasing meanscomprises a coil spring acting between said housing and said detonatormember.

12. A fuse structure according to claim 1 in which said retainer is aheat softenable element.

13. A fuse structure according to claim 1 in which said means forigniting said second charge comprises a fourth charge on the side ofsaid valve means opposite said second charge and adapted to becomeignited upon impact, said fourth charge being stationarily supported insaid housing, a member adapted to impact said fourth charge and engagedby said detonator member in said first position thereof so as to be heldagainst movement in said housing while being released for movement insaid housing when said detonator member moves from said first positionthereof to said second position thereof, said member being movablyconnected to said housing so as to impact against said fourth chargewhen said explosive device impacts against a surface, and a passageextending through said member from said fourth charge to the side ofsaid valve means opposite said second charge.

1. In a fuse structure for an explosive device: a tubular housing havinga first ignitable charge at one end operable when ignited to detonatethe explosive device, a detonator member in said housing having a firstposition remote from said first charge and a second position adjacentsaid first charge, said member carrying a second ignitable chargeoperable when ignited to ignite said first charge only when saiddetonator member is in the said second position thereof, biasing meansurging said detonator member toward the said second position thereof, aretainer in said housing engaging said detonator member and holding itin said first position thereof and releasing said detonator member inresponse to ignition of said second charge, a third charge in saidhousing near the end of said housing opposite said first charge, anigniter cap on said housing operatively disposed adjacent said thirdcharge for igniting said third charge when actuated, said third chargebeing operable when ignited to influence said retainer and release saiddetonator member to move to said second position thereof, valve means onthe side of said second charge facing away from said third charge, saidvalve means being held closed by said detonator member when the latteris in the said first position thereof and being released when saiddetonator member moves away from the said first position toward the saidsecond position thereof, and means on the opposite side of aid valvemeans from said second charge operable for igniting said second chargeonly when said valve means is released.
 2. A fuse structure according toclaim 1 in which said third charge is a delayed action rod-like chargeand has one end near said igniter cap to be ignited thereby and theother end near the side of said valve means opposite said second chargeand provides the said means to ignite said second charge when said valvemeans is released.
 3. A fuse structure according to claim 1 in whichsaid valve means comprises a flap valve which is clamped in closedposition by said detonator member in the said fist position thereof. 4.A fuse structure according to claim 1 in which said valve meanscomprises a disc having a bendable flap element therein, and a clampring for holding said flap element in closed position and disposedbetween said flap element and said detonator member so as to releasesaid flap element only when said detonator member moves away from itssaid fist position.
 5. A fuse structure according to claim 1 whichincludes a cup-like element on the side of said first charge facing saiddetonator member and opening toward said detonator member so as toreceive the end of said detonator member when the latter moves into itssaid second position, the side of said element facing said first chargehaving a central conical recess and said element being operable totransmit igniting shock to said first charge only when the end of thedetonator member is disposed in said element.
 6. A fuse structureaccording to claim 5 in which said detonator member is tubular and isformed of material which will not break when the said second charge isignited, said detonator member having an outside diameter slidablyfitting in said housing while the end part of said detonator memberfacing said first charge has a diameter receivable in the open side ofsaid cup-shaped element.
 7. A fuse structure according to claim 1 whichincludes a choke between said igniter cap and said third charge.
 8. Afuse structure according to claim 2 which includes a choke between saidthird charge and said second charge.
 9. A fuse structure according toclaim 1 in which said means for igniting said secoNd charge comprises afourth charge on the side of said valve means opposite said secondcharge and adapted to become ignited upon impact, support means in saidhousing supporting said fourth charge and engaged by said detonatormember in said first position thereof so as to be held against movementin said housing while being released for movement in said housing whensaid detonator member moves from said first position thereof to saidsecond position thereof, said support means being movably connected tosaid housing for movement of said fourth charge into impactingengagement with said housing upon impacting of said explosive deviceagainst a surface.
 10. A fuse structure according to claim 9 in whichsaid support means has one end facing said detonator member and the saidfourth charge mounted on the other end thereof and a passage extendingthrough said support means from end to end thereof.
 11. A fuse structureaccording to claim 1 in which said biasing means comprises a coil springacting between said housing and said detonator member.
 12. A fusestructure according to claim 1 in which said retainer is a heatsoftenable element.
 13. A fuse structure according to claim 1 in whichsaid means for igniting said second charge comprises a fourth charge onthe side of said valve means opposite said second charge and adapted tobecome ignited upon impact, said fourth charge being stationarilysupported in said housing, a member adapted to impact said fourth chargeand engaged by said detonator member in said first position thereof soas to be held against movement in said housing while being released formovement in said housing when said detonator member moves from saidfirst position thereof to said second position thereof, said memberbeing movably connected to said housing so as to impact against saidfourth charge when said explosive device impacts against a surface, anda passage extending through said member from said fourth charge to theside of said valve means opposite said second charge.